1. Field of the Invention
This invention relates to the field of computer accessories and more particularly to the field of workstations for computer terminals. More particularly still this invention relates to ergonomically designed workstations for computers which workstations minimize the development of debilitating work related illnesses and symptoms due to so-called repetitive strain injury, frequently referred to as RSI.
2. Description of the Prior Art
Computers, and particularly small digital computers, commonly referred to as personal or microcomputers (PC's), or occasionally also minicomputers, have become one of the most ubiquitous and rapidly proliferating developments of modern technology. Such computers have become almost indispensable business and scientific tools, used by nearly every level of worker from the lowest level clerk to corporate managers and presidents as well as by many individuals in their own homes, both for business and for recreation. The inherent speed of the electronic computer, which speed ever increases and allows it to handle masses of data and almost impossible calculations, makes the digital computer one of the most widely used as well as the most representative tools of the modern age. Once learned, the techniques of computing multiply the effectiveness of single individuals in handling repetitive data and as well as the speed and accuracy of complicated calculations and are responsible for the computer within a few short years, becoming almost a "wonder machine".
With the development and growth of the use of computers, a great number of accessory devices have been developed to enhance their basic effectiveness as well as to make the working environment of the computer operator more pleasant and efficient. However, along with the extraordinary benefits of the computer have come a number of persistent problems, including health problems. One of the greatest of these is related to the very nature of the computer, i.e. its astounding ability to handle masses of data and to accept instructions very quickly.
A computer itself, and particularly the digital, small computer, derives much of its flexibility from its ability to take a large number of repetitive instructions quickly and efficiently and to operate using such instructions at a very rapid rate. Normally an operator must provide the computer with its basic instructions and, in many cases, much of its original data, which means that an operator must operate the keyboard of the computer to either feed in data to the computer or program it. However, operators are subject to error and, since a computer is basically a stupid machine, which must either operate with whatever instructions and data it is provided or reject such data, causing the processing of the data to stop until corrections are made, it is necessary for the operator to check as the instructions are fed to the computer that, in fact, the proper instructions are being entered. Such verification operation is accomplished by having a Video Display Terminal (VDT) in the form of a cathode ray tube (CRT) upon which the instructions which are being fed to the computer are displayed for simultaneous checking by the operator. The VDT also displays instructions to or warnings to the operator from the computer to either guide the operator's handling of the data or instruction input or to warn the operator of malfunctions or mistakes.
The introduction of the VDT or Video Display Terminal for checking the operation of the computer, as well as the efficiency of the operator in coding in instructions, introduced a new factor into the environment of those who had traditionally operated keyboards, i.e. typists or typewriter operators who used a familiar keyboard which, after some practice, was memorized and required little actual monitoring. The typist operator previously could either let his or her eyes wander or, if typing data from a written memorandum, could focus upon the memorandum, which was placed very near to the keyboard. Such printed material has been traditionally placed fairly close to the keyboard so that the eye span between the keyboard and the material being typed is relatively small, minimizing the effort involved in moving the eyes from one to the other and also minimizing difficulty in focusing on both the material being typed and the keyboard. In transcribing dictation, furthermore, the typist's eyes have traditionally been able to wander, while their fingers flew over the keyboard, converting the words of the dictation into printed material, which was checked from time to time by the typist's eyes. Even with such minimum movements of the eyes, however, the repetitive hand and finger movement necessary in typing could become extremely tiring after several hours and the typist frequently also encountered strain due to the repetitive motion of the typing itself, even after much practice.
The introduction of the Video Display Terminal, or VDT, upon the introduction of computers with a conventional large monitor, however, introduced a new element into the equation of bodily comfort and health in that the video monitor required fairly frequent periodic checking to make certain the correct information was being applied to the keyboard. With the small restricted size of certain monitors applied to a conventional typewriter somewhat after the introduction of computers, the problem introduced by the monitors was not particularly great, because the monitor itself was small and was invariably mounted directly on top of the typewriter so that it was very close to the keys of the typewriter and required only a minimum movement of the eyes to focus upon. However, the normal Video Display Terminal or VDT associated with a computer is of fairly large dimensions so that it may be easily readable by the operator when there is a large amount of data displayed upon it.
Consequently, the very size of the video monitor prevented such monitor from being normally placed in close association with the keyboard of the computer. The video monitor, furthermore, because of it size, normally is fairly heavy and requires a substantial support, if it is to be secure. As a result, the custom grew of placing the video monitors or VDT, upon a conventional desk top, which invariably has sufficient strength to support the VDT along with the computer itself, and to have the keyboard attached to the computer by a cable so that the keyboard could be easily placed in front of the monitor.
In recent years the video monitor has increased very significantly in size so it can display more data at a time, particularly in spreadsheet form, while still providing a readable display. Such large monitors introduce significant difficulties in placement and support of the monitor in a convenient position for the operator.
Within a short time after the introduction of the VDT, specialized desks or "workstations" were developed, usually incorporating a basic desk or working top and frequently having shelves on the back for the receipt of various associated equipment. By connecting the CPU, or Central Processing Unit, to the keyboard and to the monitor by separate cables and/or wiring, the CPU could either be placed upon the desk top or on one of the shelves and the video monitor could also be placed either upon the desk top or working surface or upon the CPU cabinet or upon one of the shelves and the keyboard could be placed by the operator in whatever location they wished upon the work surface. The video monitor, therefore, became traditionally placed at about eye level in front of the operator while the keyboard was placed in front of the video monitor on the work surface. Various operators, however, might place the video monitor upon any work surface they found convenient and comfortable and place the keyboard in a position on the available work surface which they found comfortable.
Since long hours are normally worked in front of a computer by the operator, it was found that the operator, after a few hours, might become very uncomfortable. Statistical studies of the complaints of computer operators have found very elevated occurrences of musculoskeletal discomfort in Video Display Terminal operators, as compared with other workers during similar work, for example, typists. Statistical studies have shown a high correlation between VDT use and shoulder, neck and other discomfort and pain as well as so-called "wrist tendonitis". Such various discomforts and disorders may be broadly referred to as "repetitive strain injuries" (RSI) or sometimes cumulative trauma disorders. Such RSI disorders or injuries usually occur when a person repeats the same motion many thousands of times a day. It is exactly this type of repetitive motion which is most characteristic of the operation of computer terminals, particularly in those cases where the operator must essentially type for long periods such as is done by stenographers and data processing personnel.
Not only are there repetitive motions of the hands in the basically typing of data into a computer terminal, but the operator is continuously glancing from the keyboard, which incorporates certain keys which even the skilled typist normally has not memorized, to the video terminal to check on the data which is being fed into the computer. This also requires continuous movement of the eyes back and forth between the computer terminal and the keyboard and also sometimes to a third work surface where material in printed form is displayed which is being fed into the computer. In some cases, it may be necessary only to move the eyes, particularly if the operator does not wear glasses. However, because of the normal distance between the keyboard and the monitor as a result of the size of the monitor, the movement of even the eyes quickly tires the muscles of the eyes providing eye strain and, where the head is moved, such movement of the head and neck quickly leads to musculoskeletal discomfort of the neck, particularly in older operators.
Thus, one of the serious problems related to use of a computer terminal is that of neck and back strain. This is created by continuously sitting in a difficult position due often to the location of the monitor, the keyboard or both in relation to the position of the operator's chair. Particularly if the monitor is at a distance or is far off center, as is, in fact, sometimes preferred by some operators, at least initially, the operator may sit in a basically uncomfortable position for long periods of time. Furthermore, if the keyboard is too far from the operator's seat or is an uncomfortable height, a similar discomfort may rapidly occur. Thus, during the working periods of a computer operator, since it is frequently necessary to look from the monitor screen and back again in order to perform various tasks, if the computer equipment components, i.e. the keyboard and the video monitor, are not in advantageous or comfortable positions, strain to the muscles of the neck and the eyes may quickly occur.
It has been suggested before that it is ergonomically preferable to have the keyboard and the monitor screen located fairly close to each other and at about equal height, as well as at customarily comfortable distances from the eye of the user in order to minimize head movements and eye focusing adjustments, which may, after a long, continued activity, produce considerable physical stress in the muscles and related structure and physiology of the operator.
Incorrect keyboard and monitor screen positioning are particularly taxing to computer operators who wear corrective lenses, since such operators may have relatively little ability to focus their eyes easily at different distances or may even frequently be reduced to peering at one or the other or both of the monitor screen and the keyboard around the edges of bifocal corrective lenses.
One particular problem relating to the operation of computers which has been forced more and more prominently upon the attention of both medical and industrial hygiene personnel in recent years is the RSI or cumulative trauma disorder commonly known as carpel tunnel syndrome. Carpal tunnel syndrome is an unusually debilitating injury to the wrist joint frequently attributed to very long continued repetitive hand motions. Because the median nerve and flexor tendons of each hand pass through a relatively small opening in the wrist joint known as the carpel tunnel, if the walls of such tunnel become constricted, pressure may be placed upon the nerves in particular, and cause pain which can at times become excruciating. Long continued activities of the hand involving strain on the wrist combined with repetitive finger articulations may result in swelling of the carpel tunnel walls such that pressure is exerted upon the median nerve where it passes through the carpel tunnel with resulting pain, tingling and numbness of the fingers which are typical symptoms of carpel tunnel syndrome. The usual medical treatment involves either complete immobilization of the wrist for a period of time to allow the swelling to decrease or disappear, or, alternatively, surgery to relieve the pressure or basically enlarge the carpel tunnel area so that considerable more swelling is necessary to cause serious pressure upon the nerve. However, it has been found that once carpel tunnel syndrome occurs, the likelihood of a recurrence is fairly high. Considerable lost work time may thus occur because of carpel tunnel syndrome and the loss of the services of skilled computer operators through temporary inability to operate computer terminals and/or necessary transfer to other tasks assumes very large proportions. Carpel tunnel syndrome, in fact, now constitutes a fairly large proportion of workmen's compensation-type injury and many industries have been seeking a solution.
There have been a number of recent studies to determine various ways of preventing the occurrence of repetitive strain injury, or RSI, in computer operators and various computer manufacturers have undertaken to design equipment which is adapted to lower the probability of the development of RSI by computer operators. Such equipment has depended largely upon improving the operator's position relative to the video monitor at the workstation so as to minimize stress upon the wrist, forearms and shoulders of the operator. Various improvements including the use of arm rests, wrist rests, and foot rests in conjunction with Video Display Terminals, or VDT, workstations have been tried and various means for locating computer screens and keyboards of computer workstations to make the station more comfortable have been developed or tried. In most of these arrangements the aim has been to allow the computer operator to adjust the position of the VDT, or Video Display Terminal, to a particularly comfortable viewing position as well as to adjust the keyboard to a position favored by the operator. In addition, operators have been trained to use easier and lighter keystrokes and particularly to take more frequent rests. While all these expedients have tended to decrease repetitive strain injury, or cumulative trauma disorders, the large problem of Repetitive Strain Injury, or RSI, has not been completely solved by any means and carpel tunnel syndrome, in particular, continues to be a serious problem among computer operators, not to mention the traditional "pain in the neck" and/or headache which seem to be particularly prevalent among computer operators and typists. One attempt to legislate an end to the problem has been that undertaken by the city of San Francisco which within the last several years passed an ordinance requiring certain equipment standards for employees whose duties include routine repetitive keyboard motions for more than four hours, inclusive of breaks per any eight-hour shift. Such ordinance makes it mandatory for employers to provide such operators with user adjustable workstations and chairs that meet various minimum standards, including provision for arm rests, wrist rests and foot rests, if the operator so requests, to enable the operator to maintain a neutral position of the wrist while at the workstation keyboard.
As a result of the problems set forth above, various attempts at solving repetitive strain injury difficulties have been made by various inventors and manufacturers as set forth, for example, in the following patents which have been issued within the past several years.
U.S. Pat. No. 4,381,714 issued May 3, 1983 to H. H. Henneberg et al. discloses an early vertically adjustable computer console table using a gas cylinder to infinitely adjust a computer work surface to attain the best height for the operator in order to increase efficiency and contribute to health.
U.S. Pat. No. 4,637,322 issued Jan. 20, 1987 to J. F. Hampshire et al. discloses an adjustable work table for computers which is tilted by means of a compound arcuate tilting mechanism and support activated by a rack and pinion arrangement which allows the arcuate supporting members to rock the arcuate tilting mechanism with a minimum of vibration. The workstation supporting table is also adjustable with respect to height by a scissors arrangement. Both the tilting mechanism and the elevating scissors arrangement are operated by rotating knobs. It is stated that the supporting surface for the cathode ray tube can be adjusted both vertically and rotationally about a horizontal axis to align with the operator's line of vision.
U.S. Pat. No. 4,852,500 issued Aug. 1, 1989 to J. B. Ryburg et al. discloses a computer workstation in which in general, the monitor or CRT and the keyboard are mounted upon movable slides, Preferably the central processing unit is also mounted upon the slide upon which the CRT is mounted and the CRT is in turn mounted upon a fairly long articulated arm which is in turn mounted upon the CRT slide. Such articulated arm allows the CRT to be moved upwardly and downwardly as well as moved in and out while the slide provides sidewise movement. Consequently, the CRT is provided essentially with universal movement or adjustability albeit with a rather expensive arrangement. The keyboard is not coordinated with the movement of the CRT support arm, but merely slides toward and away from the operator. One aim of the Ryburg et al. arrangement is to be able to move the CRT out of the way at the workstation when not being used. Several alternative articulated arm arrangements are shown for the monitor, all of which are mounted on slides.
U.S. Pat. No. 5,033,804 issued Jul. 23, 1991 to S. M. Faris discloses a unitary workstation mounted centrally upon a desk. The station is basically in the form of a unitary module. The unitary workstation module may be essentially rotated or positioned with various inclinations from flat matching the desk top to almost vertical depending upon the operator's inclination or desire either manually pivoting or by pivoting or rocking with power means. The CRT is mounted behind glass in the center of the module and the keyboard is mounted at the bottom. All the parts of the station including the CPU are contained in the module below the CRT and keyboard so no movable cables are involved. The keyboard does not appear to be individually adjustable with respect to the position of the CRT monitor.
U.S. Pat. No. 5,041,770 issued Aug. 20, 1991 to M. A. Seller et al. discloses a computer workstation in which the monitor and keyboard are supported upon separate elevatable supports. The supports are operated by electric motors. The monitor support can be moved forward and backward as well as up and down and the keyboard support can be moved to various angles. An adjustable wrist support is also provided adjacent the keyboard support. One of the expressed objects of the invention is said to be to allow the supports to be quickly and easily adjusted by the user to prevent the tasks being performed from being repetitive with possible physical injury such as carpel tunnel syndrome. Adjustment is by power means.
U.S. Pat. No. 5,044,284 issued Sep. 3, 1991 to M. Gross discloses a computer workstation in which either the CRT or the entire computer combined with the CRT is mounted upon an adjustable shelf which is pivoted at the front and supported in the rear with a belt such that tightening the belt results in adjusting the angle of the shelf and the CRT support thereupon. The forward-rear position of the CRT or computer may be adjusted by the position of a rear panel on the shelf. A separate forward shelf is positioned in front of the CRT and pivoted at the near end in slots in the shelf supporting structure and supported by a pivot arm supporting the shelf on the opposite side. It is said that the position of the two shelves can be adjusted with a minimum of effort by the operator while seated to obtain a comfortable position of the two for use by the operator.
The adjustments are clearly not intended to be done frequently, but only when adjusting the workstation for a new operator.
U.S. Pat. No. 5,071,204 issued Dec. 10, 1991 to M. J. Price et al. discloses a desk-type computer workstation having a transparent central top with a CRT monitor supported at an angle on an adjustable shelf under the top. A keyboard is slideably mounted on a tray with a conventional drawer slide in front of the monitor shelf. The monitor shelf can be adjusted upwardly and downwardly and to various angles of inclination as desired by a variable pin arrangement, but is not readily adjustable at will.
U.S. Pat. No. 5,094,514 issued Mar. 10, 1992 to P. O. Grosch discloses a computer workstation furniture-type piece in which the CRT and frequently the computer also are mounted or supported upon a shelf within an opening below the main work surface. The shelf is mounted on a series of alternate pegs or the like in an inclined position. The top of the workstation furniture piece opens or pivots up to allow the operator to view the screen of the CRT and has a surface on its underside upon which printed material may be supported immediately above the CRT screen. A keyboard shelf meanwhile pulls out so it is available to the operator and also is out of the way of the operator's line of sight to the CRT screen.
U.S. Pat. No. 5,118,172 issued Jun. 2, 1992 to C. V. Ugalde discloses a computer workstation having an in-and-out sliding keyboard support at normal operating height plus an inclined shelf in back of and below such shelf to support the monitor in a position so that the operator may move his or her eyes only minimally up and down to shift their view from the keyboard to the monitor and back. The operator's view of the monitor is always maintained downwardly at an angle.
U.S. Pat. No. 5,120,117 issued Jun. 9, 1992 to C. L. Williams discloses an ergonomically designed computer station comprised of a plastic tray-type support designed to be mounted within a cutout section of a desk or counter top. The depth of the tray is designed to place the keyboard at a good physiologic height of about 26.5 inches recommended for typewriters from the floor when mounted in a standard 29.5 inch worktable height. The monitor position is set at a small angle from the keyboard section. There is also a wrist support. There are no adjustable features.
U.S. Pat. No. 5,161,760 issued Nov. 10, 1992 to W. H. Terbrack discusses at some length the medical problems associated with long continued repetitive movements and provides adjustable arm, wrist and hand rests to aid in support of the arm and hand during use of a computer keyboard.
U.S. Pat. No. 5,174,223 issued Dec. 29, 1992 to M. K. Nagy et al. discloses a computer workstation having an elevation means for raising or lowering of the computer support table. Attached to the table is a keyboard stand that can be inclined to various positions and incorporates an arm rest to aid in supporting the arms. This is alleged to provide an ergonomically arranged workstation.
U.S. Pat. No. 5,174,224 also issued to M. K. Nagy et al. on Dec. 29, 1992 is a continuation-in-part of the previous Nagy patent showing a keyboard support.
While, as will be recognized from the above, there have been a number of efforts to decrease the problem of Repetitive Strain Injuries, or RSI, and each of such efforts has, in fact, been successful to a certain extent or degree, no overall solution has been as yet found. While providing a comfortable workstation certainly tends to alleviate the symptoms of RSI for a period of time and while it is recognized that due to variations in build, physical condition and personal idiosyncrasies, it is advantageous to allow a computer operator to be able to adjust the position of the video monitor and the keyboard to his or her own most comfortable positions and that this will tend to at least considerably delay the development of actual symptoms of RSI, such symptoms continue ultimately to manifest themselves among many computer operators.
After a long continued study or this problem, the present inventor has found that the previous workers have been largely directing their efforts towards mere palliatives or decreases of the symptoms rather than directly addressing the heart of the RSI problem. After long continued study, the inventor has established the following, (a) that while it is advantageous to have the computer operator adjust the components of the workstation to the most comfortable position for that particular computer operator, that said comfortable position continues for only a relatively short time, (b) after a given position becomes uncomfortable, the operator must be able to assume a different position quickly and easily, and (c) that the operator will only assume a more comfortable position if the apparatus can be adjusted instantaneously and with no significant effort.
The applicant inventor, therefore, has developed a computer workstation system which allows and encourages the operator to adjust the relationship of the video monitor and the keyboard in an infinitely variable number of relationships with respect to the operator as operation of the computer continues so that former completely repetitive motions become significantly changed, and due to such change in the overall repetitive motion due to the change in position, RSI injury is significantly decreased and operator comfort is materially enhanced. Applicant inventor accomplishes these aims by taking into account certain physiological relationships and has developed an apparatus which can be conveniently readjusted by the computer operator, not only whenever such operator becomes uncomfortable, but at any time the notion strikes the operator or preferably at rather frequent intervals whereby the repetitive motions of the eyes and the fingers and the hands which are essentially inherent in the operation of a keyboard and a computer monitor are continuously slightly varied throughout the work period so that they are not exactly the same, but are continuously changing, thus very greatly enhancing the comfort of the operator and the aim of eliminating RSI injury. Furthermore, the operator essentially becomes responsible for their own comfort by maintaining healthful operating equipment parameters so that the operator can himself or herself determine how likely he or she is to develop RSI injury.